This invention relates to a self-propelled tree pruning apparatus.
Trees are pruned for many reasons. However, commercial pruning of forest trees, such as Douglas fir and ponderosa pine, is undertaken primarily to produce trees having knot-free clearwood in the pruned area of the tree. When the lower branches of young forest trees are properly removed, occlusion or covering over of the removed branch stub takes place as the tree grows, thereby providing knot-free clearwood in the pruned area when the mature tree is harvested. Effective pruning requires that all branches, regardless of size, be removed up to a height of about thirty feet from the ground. Factors affecting rapid occlusion include trim angle, closeness of cut, and cut quality (i.e., smoothness of cut).
Currently the standard pruning method involves manual pruning using saws and hand shears. Manual labor is unsatisfactory for a number of reasons, such as safety, cost, and use of incorrect pruning techniques by untrained workers.
A number of pruning machines have been suggested. Some, such as the "Tree Witch", are hydraulically powered; some, such as the "Tree Monkey", are gasoline powered. Some use shearing devices for pruning; some, such as the Tree Monkey, use chain saws. All of these devices are difficult to operate and maintain, and do not provide the same quality of cut as manual pruning.
It is an object of the present invention to provide a self-propelled tree pruning apparatus which is easy to use and maintain, prunes rapidly, and provides a cut equal or superior to that of mechanical pruning.